The couple will be double dating with country singer Kix Brooks and his wife Barbara – but it's not the ladies who are having last-minute wardrobe worries.

"Kix is going to kill me for talking about this, but we've been going back and forth texting like a couple of girls! I'm all, 'What are you wearing?' And he's sending me pictures of things he's got pulled out," Bentley, 39, tells PEOPLE Country.

"So I went to a little preppy shop in Nashville and I'm taking pictures and sending them back to Kix like, 'What do you think of this?' "